The present invention relates to an information recording system using a magnetic recording method, and in particular to a magnetic recording apparatus that is capable of operating at 20 times or more than the current recording capacity of the information recorded on the media.
The fact that it is possible to record magnetically information at densities of more than 1 Gigabits per square inch was announced by IBM in 1990. This announcement (for example, Ching Tsang et al. "Gigabit density recording using dual-element MR/inductive heads on thin-film disks", IEEE Transactions on Magnetics, Vol. 26, No. 5 (September 1990), pp. 1689-1693) indicates, based on the results of measuring the error rate, to what extent the recording density can be increased when the flying height of the head is reduced to below 0.05 microns when a dual element head comprising an inductive head in the recording portion and a magnetoresistive head in the reproduction portion is used in combination with a sputtered thin film recording medium, but does not carry out the tracking of the head, etc. Hence, it does not operate as a recording apparatus.
In addition, the discrete type media structure in which a groove is provided on both sides of the recording track in the medium has been published in, for example, S. E. Lambert et al. "Reduction of edge noise in thin film metal media using discrete tracks", IEEE Transactions on Magnetics, Vol. 25, No. 5 (September 1989), pp. 3381-3383. The purpose of this paper is to reduce the media noise that occurs at the edge of the recording track and deals with experiments on media with recording track widths of around 10 microns. However, they have concluded that there is no effect of making the medium have a discrete structure as far as the signal to noise ratio (S/N ratio) and the error rate are measured.
On the other hand, known examples of providing several sectors on the information recording surface and determining the head position based on this have been shown in, for example, H. Nakanishi et al., "High track density head positioning using sector servos", IEEE Transactions on Magnetics, Vol. MdG-19, No. 5 (September 1983), pp. 1698-1700. In this publicly known example, there is the problem that it is necessary to form newly the pattern for determining the head position on the medium recording surface and hence the data storage region gets reduced by a corresponding amount.
Further, an optical servo equipment for controlling the position of the magnetic head is described in Japanese Patent Laid-Open No. 59-8172 (corresponding to U.S. Pat. No. 4,633,451). In this prior art, the position of the head is determined by providing a layer of different optical reflectivity on top of the medium recording layer and reflecting a laser beam by this material layer. Therefore, the distance between the magnetic head and the medium recording layer increases and becomes extremely disadvantageous for carrying out high density recording.